New Type of Solar Array Provides Twice as Much Power as Normal Panels

Researchers at the University of Arizona have developed a new method for turning solar energy into useable electricity. They have designed a solar module which works rather like a telescope. It uses a curved mirror to focus sunlight onto a small glass ball which then spreads the light evenly across a solar panel made up of high efficiency solar cells, normally only used in space. The whole module can provide twice the power output of a normal solar panel.

The solar panel is mounted on a frame which tracks the sun during the day. Blak Coughenour, a graduate student at the University’s College of Optical Sciences, explained that “the tracker is fully automated. The system wakes itself up in the morning and turns to the East. It knows where the sun will rise even while it’s still below the horizon. It tracks the sun’s path during the day all the way to sunset, then parks itself for the night.”

Mirrors are already used in solar thermal plants, but this mirror had to be specially designed. Normally mirrors are used to focus the heat from the sun onto a specific point, such as a pipe, but this mirror was designed to concentrate the sunlight.

“Most mirrors used in solar power plants are used for thermal generation by focusing light onto a long pipe used to heat water into steam. This requires the mirrors to be shaped like a cylinder. What we have learned here at the Mirror Lab is how to bend the glass to high accuracy so as to focus to a point or a line.”

Even so the new mirror still focuses a lot of heat onto the solar cells. In order to cool the panel a system of fans and a radiator are used to keep the whole array within 36 degrees of the surrounding temperature. However, heat is still a valuable source of energy so new designs are being drawn up which will “use the mirrors to create an eco-friendly furnace that works like a toaster oven to burn a mold into a flat sheet of glass.”

Preliminary tests suggest that a module with two mirrors could produce enough energy for two homes. Plans exist to include eight mirrors on each tracker.

“An array of sun trackers on an area measuring about seven by seven miles (11 x 11 km) would generate 10 GW of power during sunshine hours – as much as a big nuclear power plant.”